By Nate Raymond

NEW YORK (Reuters) - The accused mastermind behind the underground website Silk Road will be sentenced on Friday for orchestrating a scheme that enabled more than $200 million of anonymous online drug sales using the digital currency bitcoin.

Ross Ulbricht, 31, faces up to life in prison after a federal jury in Manhattan found him guilty in February of charges including conspiracy to commit drug trafficking, money laundering and computer hacking.

Prosecutors are seeking a sentence "substantially above" the 20-year mandatory minimum that U.S. District Judge Katherine Forrest must impose on Ulbricht, who admitted to creating Silk Road but denied wrongdoing.

Ulbricht is expected to appeal his conviction. His lawyer declined comment ahead of sentencing.

Silk Road operated for more than two years, allowing users to anonymously buy drugs and other illicit goods and generating over $214 million in sales in the process, prosecutors said.

The online black market was shutdown in October 2013, when authorities seized the website and arrested Ulbricht at a San Francisco website.

Prosecutors said Ulbricht operated the website under the alias Dread Pirate Roberts, a reference to a character in the 1987 movie "The Princess Bride."

The website relied on the so-called Tor network, which lets users communicate anonymously, and accepted bitcoin as payment, which prosecutors said allowed users to conceal their identities and locations.

Prosecutors said Ulbricht, who grew up in Austin, Texas, took extreme steps to protect Silk Road, soliciting the murders of several people who posed a threat. No evidence exists the murders were carried out.

At trial, Joshua Dratel, his lawyer, said Ulbricht had indeed created what he intended as a "freewheeling, free market site" where all but a few harmful items could be sold.

Dratel said Ulbricht handed off the website to others after it became too stressful, and was lured back toward its end to become the "fall guy" for its true operators.

In a letter filed in court last week, Ulbricht urged Judge Forrest in sentencing him to leave a "small light at the end of the tunnel" and said he recognized Silk Road was a "very naive and costly idea."

"In creating Silk Road, I ruined my life and destroyed my future," he wrote.

The case is U.S. v. Ulbricht, U.S. District Court, Southern District of New York, No. 13-06919.

(Editing by Andre Grenon)